Calcaneal fracture with a concomitant unstable subtalar dislocation: A case report

Traumatic dislocation of the subtalar joint is an infrequently occurring injury, first described by DuFaurest in 1811. They were later on classified by Broca as medial, lateral, posterior and anterior dislocations based on the direction of the dislocation.

We present a case of a 30 year old male who presented after a 5 m height fall and direct right foot trauma. Investigations done in the emergency department revealed a right subtalar lateral dislocation with associated calcaneal intraarticular displaced fracture. Open reduction internal fixation of the calcaneal fracture was decided alongside with reduction of the subtalar joint. Intraoperatively the subtalar reduction was totally unstable due to the deficiency of the lateral collateral ligament. A decision of reconstruction of the calcaneofibular ligament using a synthetic ligament was taken. This reconstruction resulted in an adequate intraoperative stability of the subtalar joint. On a 2 year follow up the patient was asymptomatic with no residual subtalar instability.

These injuries must be suspected after high energy trauma or twisting forces in the foot. They occur more frequently in men than in women and predominately affect people in their mid-30 s. Our case is unique in that the reconstruction of the calcaneofibular ligament was done using a synthetic graft to stabilize an acute unstable subtalar joint dislocation.

Subtalar dislocation is a rare injury with post reduction instability being even rarer. Care has to be taken not to overlook the frequently associated bony injuries, due to their impact on treatment decision and prognosis.